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from &| inches square to 1 inches in diameter was wholly insufficient to give a proper structure, so that little weight can be attached to the determination on any one bar. This renders it dif-
TABLE XVII-B. Influence of Silicon on the Tensile Strength.
					4	n	<H	H^    -  1
				2	S	* & cj 	O	O df^ g fl
				71	o	o'^ 	^pq	"S    d P-
	.Chemical composition ;			l-s 43	so g	a f S  oj	O CO o S	Iflfl
	.per cent.			P-" flj	1	 S  gp	nS	*W     *C <D
				-D 	*co	"*/?<H ^* P*^5	>.	O *^.S n ^
				Jl	g .	<S'<SS8	S	,J I'eo^'S
1				s?:  +3 <c	d) CD V cU	|1|1	 O .2	Bill's
B'	C	Si	Mn	p-p,	^	^^   .	W	g..^
B	18	.77	.21	76160				
C	19	1.57	.28	84000	7840	6840	0.80	85
D	20	2.14	.25	88480	12320	10320	1.37	75
E	20	2.67	.25	95200	19040	17040	1.90	90
IP	21	3.40	.29	106400	30240	27240	 2.63	104
G	25	4.30	.36	109760	33600	26600	3.53	75
H	26	5.08	.29	107520	31360	23360	4.31	54
ficult to calculate the exact effect of silicon^ especially since the bars A and B present contradictions. .Thus B contains .04 per cent, more carbon than A, .07 per cent, more manganese, and .56 per cent, more silicon,, and yet has only 2240 pounds more tensile strength per square inch.
 Inspection shows that A is probably the erratic member, for its strength is too high for its composition. Moreover, the annealed bars show a loss in strength of 34 per cent, from the natural in A., while bars B, C and D give 15, 12 and 14 per cent., respectively, so that it is likely.that A. is finished at too low a temperature and has a-higher strength than really belongs to it. For this reason it will be set aside as abnormal, and in Table XVII-B the bar B is taken as a basis from which to investigate the differences in .tensile strength. '3STo allowance is made for manganese, since this element is fairly constant in all the specimens, but a value of 1000 pounds per square inch is given to carbon, according to the results given in Section XVIIm. After this allowance the remaining variations are ascribed to silicon, but as no data are at hand concerning the content of phosphorus/ the answer is open to question.